Absorption and Fluorescence Properties of 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-ethylhexyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione. A Covalent Fluorescence in Solution and in the Solid State

Authors

Roza Al-Aqar, Department of Chemistry, College of Science, University of Basrah, Basrah, IraqFollow

Abstract

In the current article, the photophysical properties of 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-ethylhexyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione were investigated. The visible absorption bands at 527, 558, and 362 nm in propylene carbonate, and the compound was found to be fluorescent in solution and in the plastic film with emission wavelengths between 550-750 nm. The Stokes Shift of P.C., acetonitrile, diethyl ether, tetrahydrofuran (THF), cyclohexane, dibutyl ether, and dichloromethane (DCM) are 734, 836, 668, 601, 601, 719, and 804 cm⁻¹, respectively. The Stokes Shift Δ�� was less in THF and cyclohexane than in the other solvents, indicating that the energy loss is less between the excitation and fluorescence states. The photophysical characterizations were carried out on the compound in different solvents. The compound displays a 12 nm red shift in the absorption maximum in toluene compared with propylene carbonate (P.C.), where λmax was 558 nm in P.C. The compound displays 5 nm and 10 nm red shifts in the absorption maximum in diethyl ether and dibutyl ether, respectively. The absorption band is almost insensitive to the polarity of the solvent, showing only a slight red shift from 563 nm in diethyl ether to 569 nm in cyclohexane (ΔλmaxAbs��� = 6 nm) and also a red shift from 558 nm in acetonitrile to 570 nm in toluene (ΔλmaxAbs= 12 nm), which is appreciably red-shifted depending on the polarity of the solvent. The emission maxima of the dye slightly shift more toward the red region in solvents such as DCM and toluene compared to other solvents. The dye showed a slight red shift of approximately 5 nm when moving from acetonitrile to the less polar solvent, dichloromethane (DCM).

Keywords

Dihydropyrrolo, Intramolecular charge transfer, Plastic film, Red-shift, Stokes shift

Article Type

Article

How to Cite this Article

Al-Aqar, Roza (2022) "Absorption and Fluorescence Properties of 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-ethylhexyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione. A Covalent Fluorescence in Solution and in the Solid State," Baghdad Science Journal: Vol. 19: Iss. 5, Article 16.
DOI: https://doi.org/10.21123/bsj.2022.6265